package com.magic.ch02_二分与前缀和.数的三次方根;

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        double x = sc.nextDouble();
        double l = -10000, r = 10000;

        while (r - l > 1e-8) {
            double mid = (l + r) / 2;
            if(mid * mid * mid >= x) r = mid;
            else l = mid;
        }
        System.out.printf("%6f",l);
    }
}
